Specific questions about gfx card frequencies

So, I am getting a new pc after 4.5 years. Have a question though.

I will use the pc mostly for everyday use, writing, mailing, surfing etc. I play WoW, but not many other games. I will get Diablo3 when it comes out, but that is no hardware-killer either. But I want a gaming-pc, you never know what new games come out

Graphics card : I have two in mind. Both have exactly the same price, 270 swiss franks ( = 220 euro, 280 $ ). The only difference besides the producer is that one has 1 GB Ram and a GPU frequenzy of 870 Mhz, while the other has 2 GB ram but only a frequenzy of 800 Mhz.

So what is the differenze there and is that little frequenzy realy worth as much as twice the ram ?

if you're playing BF3, you'll defo want more than 1GB of video RAM, as any high AA setting or the likes will eat your gpu's memory alive and cause crashes (of course can be fixed with lower setting) With that said, frequency is almost always better to care about, but as vesseblah said you can't compare AMD/Nvidia.

if you're playing BF3, you'll defo want more than 1GB of video RAM, as any high AA setting or the likes will eat your gpu's memory alive and cause crashes (of course can be fixed with lower setting) With that said, frequency is almost always better to care about, but as vesseblah said you can't compare AMD/Nvidia.

I dont play BF3. But I hope that my new pc will still be able to run games that come after BF3.

Either will be fine, the 6950 is a solid card and the higher frequency on the Gigabyte one will likely edge out the Sapphire one assuming a single monitor setup and the cooling is sufficient(which it should be) enough for it to not down clock to compensate for the heat.

But the general question remains, what exactly does the frequenzy do and why is that 10% frequenzy increase more noticable than the 100% Ram increase ?

Is it just because my "small" resolution does never need more than 1 gb ram ? ( and no, i will not buy a bigger screen or a second screen anytime soon ^^ Probably not ever. The screen is allready too big as it is ^^ )

Much simplified:
The frequency allows for faster calculation, so better effects can be computed more rapidly (-->better effects with less lag).
The ram size is quite irrelevant unless you hit its boundaries, which happens when there's lots of data to be stored - and most notably, this happens if there's higher resolution and/or more screens. More advanced effects ofc take more space, too, but on one screen with 1680 res, I dare to say you'll be fine with 1 GB

No point mentioning these bats, I thought. The poor bastard will see them soon enough.

Short answer: If you're getting the 1gb and 2gb versions at the same price, obviously go for the 2gb.

Long answer: This discussion regarding vRAM speeds are pointless because Gigabyte has a factory overclock of 70mhz on that HD6950 1gb, something which you can do yourself. Those two cards are supposed to have exactly the same core and memory clocks, the difference being only vRAM sizes. 1gb is more than enough at 1680x1050, but at 1920x1080 or higher GPU-heavy games like Crysis/2/BF3 are known to eat upwards of 1.3gb+ vRAM.
The 1gb version is supposed to be cheaper than the 2gb version, it's something that manufactureres decided to offer as an option to those who will never use that massive 2gb buffer. If you're getting the 1gb and 2gb versions at the same price, obviously go for the 2gb.

Short answer: If you're getting the 1gb and 2gb versions at the same price, obviously go for the 2gb.

Long answer: This discussion regarding vRAM speeds are pointless because Gigabyte has a factory overclock of 70mhz on that HD6950 1gb, something which you can do yourself. Those two cards are supposed to have exactly the same core and memory clocks, the difference being only vRAM sizes. 1gb is more than enough at 1680x1050, but at 1920x1080 or higher GPU-heavy games like Crysis/2/BF3 are known to eat upwards of 1.3gb+ vRAM.
The 1gb version is supposed to be cheaper than the 2gb version, it's something that manufactureres decided to offer as an option to those who will never use that massive 2gb buffer. If you're getting the 1gb and 2gb versions at the same price, obviously go for the 2gb.

While I agree with what you say per se (should be same hardware, just a little oc), I would like to add that not everybody feels comfortable oc'ing their stuff (even though it's not that hard), and more importantly, the 1gb card has a (as far as I know, don't use it myself though) nicer cooling setup (3 fans vs 1) - that's an advantage to take into consideration, more so because the op stated he didn't plan on getting above 1680x1050 any time soon.

No point mentioning these bats, I thought. The poor bastard will see them soon enough.